Geomorphology and River Management

Applications of the River StylesFramework

Gary J. Brierley and Kirstie A. Fryirs

GEOMORPHOLOGY AND RIVER MANAGEMENT

To our families

“Every tool carries with it the spirit by which it has been created.”Werner Karl Heisenberg

Geomorphology and River Management

Applications of the River StylesFramework

Gary J. Brierley and Kirstie A. Fryirs

© 2005 by Blackwell Publishing

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Brierley, Gary J.

Geomorphology and river management : applications of the river styles framework / Gary J. Brierley and

Kirstie A. Fryirs.

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Includes bibliographical references and index.

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Contents

Preface ixAcknowledgments xi

1 Introduction 11.1 Concern for river health 11.2 Geomorphic perspectives on ecosystem approaches to river management 41.3 What is river restoration? 51.4 Determination of realistic goals in river rehabilitation practice 71.5 Managing river recovery processes in river rehabilitation practice 91.6 Overview of the River Styles framework 111.7 Layout and structure of the book 12

PART A The geoecological basis of river management 15

2 Spatial considerations in aquatic ecosystem management 172.1 Introduction and chapter structure 172.2 Spatial scales of analysis in aquatic geoecology: A nested hierarchical approach 172.3 Use of geomorphology as an integrative physical template for river

management activities 302.4 Working with linkages of biophysical processes 442.5 Respect diversity 492.6 Summary 52

3 Temporal considerations in aquatic ecosystem management 533.1 Chapter structure 533.2 Working with river change 533.3 Timescales of river adjustment 563.4 Interpreting controls on river character and behavior 583.5 Predicting the future in fluvial geomorphology 683.6 Summary and implications 75

PART B Geomorphic considerations for river management 77

4 River character 794.1 Introduction: Geomorphic approaches to river characterization 794.2 Channel bed morphology 80

vi Contents

4.3 Bank morphology 934.4 Channel morphology: Putting the bed and banks together 1044.5 Channel size 1074.6 Floodplain forms and processes 1084.7 Channel planform 1184.8 Valley confinement as a determinant of river morphology 1344.9 Synthesis 142

5 River behavior 1435.1 Introduction: An approach to interpreting river behavior 1435.2 Ways in which rivers can adjust: The natural capacity for adjustment 1475.3 Construction of the river evolution diagram 1525.4 Bed mobility and bedform development 1615.5 Adjustments to channel shape 1615.6 Interpreting channel behavior through analysis of insteam geomorphic units 1675.7 Adjustments to channel position on the valley floor 1765.8 Use of geomorphic units as a unifying attribute to assess river behavior 1845.9 Synthesis 185

6 River change 1866.1 Introduction 1866.2 Framing river evolution in context of Late Quaternary climate change 1876.3 The nature of river change 1886.4 Framing river change on the river evolution diagram 1916.5 The spatial distribution of river change 1966.6 Temporal perspectives of river change 2006.7 Appraising system vulnerability to change 202

7 Geomorphic responses of rivers to human disturbance 2087.1 Introduction: Direct and indirect forms of human disturbance to rivers 2087.2 Direct human-induced changes to river forms and processes 2107.3 Indirect river responses to human disturbance 2207.4 Spatial and temporal variability of human impacts on rivers 2257.5 (Ir)reversibility and the river evolution diagram revisited 2327.6 Synopsis 238

PART C The River Styles framework 241

8 Overview of the River Styles framework and practical considerations for its application 2438.1 Moves towards a more integrative river classification scheme 2438.2 What is the River Styles framework? 2448.3 Scale and resolution in practical application of the River Styles framework 2498.4 Reservations in use of the River Styles framework 251

9 Stage One of the River Styles framework: Catchment-wide baseline survey of river character and behavior 2549.1 Introduction 2549.2 Stage One, Step One: Regional and catchment setting analyses 254

Contents vii

9.3 Stage One, Step Two: Definition and interpretation of River Styles 2619.4 Stage One, Step Three: Assess controls on the character, behavior, and downstream

patterns of River Styles 2879.5 Overview of Stage One of the River Styles framework 292

10 Stage Two of the River Styles framework: Catchment-framed assessment of river evolution and geomorphic condition 29710.1 Introduction 29710.2 Stage Two, Step One: Determine the capacity for adjustment of the River Style 30010.3 Stage Two, Step Two: Interpret river evolution to assess whether irreversible

geomorphic change has occurred and identify an appropriate reference condition 30210.4 Stage Two, Step Three: Interpret and explain the geomorphic condition of the reach 31610.5 Products of Stage Two of the River Styles framework 323

11 Stage Three of the River Styles framework: Prediction of likely future river condition based on analysis of recovery potential 32411.1 Introduction 32411.2 Stage Three, Step One: Determine the trajectory of change 32711.3 Stage Three, Step Two: Assess river recovery potential: Place reaches in their

catchment context and assess limiting factors to recovery 33011.4 Products of Stage Three of the River Styles framework 341

12 Stage Four of the Rivers Styles framework: Implications for river management 34212.1 Introduction: River rehabilitation in the context of river recovery 34212.2 Stage Four, Step One: Develop a catchment-framed physical vision 34212.3 Stage Four, Step Two: Identify target conditions for river rehabilitation and

determine the level of intervention required 34912.4 Stage Four, Step Three: Prioritize efforts based on geomorphic condition and

recovery potential 34912.5 Stage Four, Step Four: Monitor and audit improvement in geomorphic river condition 35312.6 Products of Stage Four of the River Styles framework 354

13 Putting geomorphic principles into practice 35513.1 Introduction 35513.2 Geomorphology and environmental science 35513.3 Geomorphology and river management: Reading the landscape to deveop practices

that work with river diversity and dynamism 35713.4 The river management arena 35813.5 Use of the River Styles framework in geomorphology and river management 362

References 364Index 387

Any book reflects the personal histories and as-sociated geographic and cultural values of its authors. In a number of ways it is increasingly dif-ficult for us to separate our scientific perspectiveon rivers and their management from an emotion-al and aesthetic bond that has developed in ourwork. Working within a conservation ethos, wepromote a positive sense of what can be achievedthrough effective implementation of rehabilita-tion practices.

Perspectives conveyed in this book undoubtedlyreflect, to some degree, the distinctive nature ofthe Australian landscape and biota, the recent yetprofound nature of disturbance associated withcolonial settlement, and community involvementin river conservation and rehabilitation practices.The long and slow landscape evolution of theAustralia landmass has resulted in rivers with a distinctive character and behavior, driven by factors such as the relative tectonic stability andtopographic setting of the continent, pronounceddischarge variability, and limited material avail-ability. Remarkably few river systems comprisetruly alluvial, self-adjusting streams. Many con-temporary river forms and processes have been in-fluenced by antecedent landscape controls, such asthe nature of the bedrock or older alluvial materi-als over which they flow, and generally limited relief. Given the nature of the environmental set-ting, it is scarcely surprising that the Australianlandscape is characterized by an array of riverforms and processes that is seldom observed else-where. Across much of the continent, human dis-turbance has left a profound “recent” imprint onthis largely ancient landscape, the consequences of which vary markedly from system to system(e.g. Rutherfurd, 2000).

Along with its unique environmental settingand history of human disturbance, a distinctive approach to natural resources management that is characterized by extensive on-the-ground in-volvement of community groups has developed in Australia. Rehabilitation strategies imple-mented through Catchment ManagementCommittees (or Authorities/Trusts), LandcareGroups, Rivercare Groups, etc. have been comple-mented by core support through Federal and StateGovernment programs. Adoption of participatoryrather than regulatory approaches to river manage-ment has presented significant opportunity to incorporate research ideas into management practice.

Uptake of rehabilitation programs that strive toheal river systems in Australia has been driven byextensive involvement and leadership from thesmall group of professional geomorphologists inthe country. A significant collection of tools and techniques for river rehabilitation has beenprovided, including the National Stream Re-habilitation Guide (Rutherfurd et al., 2000), theNational Stream Restoration Framework (Koehnet al., 2001), and proceedings from various StreamManagement Conferences (Rutherfurd andWalker, 1996; Rutherfurd and Bartley, 1999;Rutherfurd et al., 2001b). Our efforts in writingthis book have been aided enormously by this in-vigorating set of research products, and the dedica-tion of various river practitioners who have “madethis happen.”

In our quest to develop a logical set of principleswith which to interpret the diversity and complex-ity of the real world, we have tried to communicateour understanding in as simple a way as possible.Duplications, inaccuracies, and inconsistencies

Preface: our personal, Australian, perspectives

Every country has its own landscape which deposits itself in layers on the consciousness of its citizens, thereby canceling the exclusive claims made by all other landscapes.

Murray Bail, 1998, p. 23

x Preface

may have arisen in cross-disciplinary use of terms,but hopefully we provide a useful platform thataids uptake and implementation of geomorphicprinciples in river rehabilitation practice.

Although this book has an unashamedlyAustralian flavor, we have endeavored to write itfrom a global perspective. We convey our apolo-gies, in advance, to those readers to whom this

book bears little semblance of reality in terms ofthe types of rivers you live and/or work with.However, we hope that the principles presentedhere bear relevance to the management issues thatyou face, and that the book provides useful guid-ance in the development of core understandingthat is required if management activities are toyield sustainable outcomes.

The River Styles framework has its origins in riverreach analysis of the Waiau River in New Zealand,in a project coordinated through SouthlandRegional Council, following a flash of inspirationgenerated by Glen Lauder. In 1994, Gary Brierleywas invited to South Africa to participate in a riverhealth workshop coordinated by Barry Hart (fromthe Australian half of the gathering). This built oninitial contacts suggested by Brian Finlayson, whorecommended an approach be made to a FederalGovernment body, the Land and Water ResourcesResearch and Development Corporation (nowLand and Water Australia; LWA) to seek support tocontinue this work. The award of a substantivegrant effectively marked the birth of the RiverStyles framework. Phil Price provided invaluableguidance in these initial endeavors – his broaden-ing of scope ensured that a generic, open-ended ap-proach was developed, moving beyond a case studyperspective. Further backing by Siwan Lovett andNick Schofield in LWA aided the coordination of early work. Collaboration with Tim Cohen,Sharon Cunial, and Fiona Nagel fashioned initialendeavors, with willing sounding boards on handat Macquarie University in discussions withAndrew Brooks, John Jansen, and Rob Ferguson.

Substantive external support through the StateGovernment agency, then called the Departmentof Land and Water Conservation (DLWC), was generated at the outset of the project. Head Officeleadership was guided by David Outhet, and on-the-ground support in the Bega Regional Office,initially by Justin Gouvernet and Don McPhee andsubstantially with Cliff Massey. The practical development and application of the River Styleswork in Bega catchment was enormously en-hanced by collaboration with the former Far South

Coast Catchment Management Committee,under leadership by Kerry Pfeiffer and funding generated through the Bega Valley Shire and theNatural Heritage Trust (NHT). Various workshopsand reports promoted early findings of the work.At one of these meetings, Michael Pitt and variouscolleagues from the North Coast Office of DLWCenvisaged potential applications of equivalentwork in their catchments. Tony Broderick played apivotal part in facilitating these applications. Atthis stage, Rob Ferguson, Ivars Reinfelds, and GuyLampert extended the range of rivers to which thework was applied through characterizations ofrivers in the Manning catchment. The primaryrole of differing forms of valley confinement,which formed a part of the PhD work completed byRob Ferguson, advanced the framework.

Subsequent developments included research onstream power along longitudinal profiles in theBellinger catchment, in work completed with TimCohen and Ivars Reinfelds. Insights into geologicalcontrols on patterns of River Styles was providedby Geoff Goldrick, in application of this work inthe Richmond catchment. Eventually more than10 catchment-based reports characterized the diversity of River Styles and their downstream patterns, in all North Coast catchments extendingfrom the Hastings to the Tweed. Rob Ferguson coordinated this work, with field work completedby Guy Lampert. Paul Batten provided the initialalgorithms to generate longitudinal profiles andstream power plots through use of GeographicInformation Systems and Digital ElevationModels. Paula Crighton was invaluable in refiningthis procedure and processing the data for theNorth Coast catchments. Practical application of the work was enhanced through a subsequent

Acknowledgments

xii Acknowledgments

contract in the Shoalhaven catchment whereRachel Nanson completed much of the field work.

A major advancement in the development of theRiver Styles framework occurred with extensionsfrom assessment of river character and behavior toanalyses of river condition and recovery potential.The PhD work of Kirstie Fryirs developed theseprocedures and applied them in the Bega catch-ment. These procedures now form Stages 2 and 3 of the framework. The development of these procedures was enhanced by a visit to Australia byScott Babakaiff (funded by LWA) and developmentof the National River Restoration Framework (in aproject with John Koehn and Belinda Cant fundedby LWA).

The next phase of the River Styles work entailedfundamental research into ecological (habitat) associations with a geomorphic classificationscheme. This work was completed by two Post-Docs (Mark Taylor and Jim Thomson), throughcollaborative funding provided by LWA andDLWC. Penny Knights and Glenda Orr supportedthis work. Collaboration with Bruce Chessmanlinked geomorphology and ecology in assessmentsof geoecological condition in Bega catchment.

Since its creation, promotion and adoption of theRiver Styles framework has occurred across the na-tion. Particular mention must be made of DavidOuthet, who promoted the adoption of the frame-work as a tool for management activities in NewSouth Wales, and provided numerous insightfulcomments on its application. Sally Boon inQueensland and David Wright in Tasmania havealso promoted the framework and have sourcedfunding for us to run courses and workshops inthose states.

Numerous members of the Rivers Group atMacquarie University have provided many hoursof enthusiastic and fruitful discussion aboutrivers. While most now roam further afield, theyremain a large part of the “history” associated withthis book. Particular mention must be made ofAndrew Brooks, Tim Cohen, Rob Ferguson, JohnJansen, Emily Cracknell, Paula Crighton, MickHillman, Pete Johnston, and Kahli McNab. MickHillman, in particular, provided the stimulus forgreatly enhancing the ‘extension science’ compo-nent of our work.

Insightful and constructive review commentson this book were made by a range of academics

and postgraduate students, including Ted Hickin,Malcolm Newson, Jonathan Phillips, Rob Fer-guson, Jo Hoyle, Nick Preston, and John Spencer.These review comments substantially improvedthe clarity and communicability of the book.

Teaching River Styles Short Courses has oc-curred in parallel to development of the framework.We wish to thank the participants of these courses,who have spanned a wide range of professions andlevels of experience from around the nation andoverseas. Their contributions have improved thepresentation of the River Styles framework and our ability to communicate and teach it. Each River Styles Short Course has been run throughMacquarie Research Limited (MRL) with adminis-trative support from Roslyn Green, Kerry Tilbrook,and Sophie Beauvais. Sophie Beauvais, IrinaZakoshanski, and Warren Bailey are thanked fortheir support in administering developments of the framework, promotion, trade-marking, and accreditation of the framework. The term RiverStyles® is a registered trademark held by Mac-quarie University and Land and Water Australia.

Most of the graphics in this book were designedby Kirstie Fryirs and drafted by Dean OliverGraphics, Pty Ltd. We thank Dean for his commit-ment to this project. We also thank colleagues inthe Department of Physical Geography, MacquarieUniversity for their support.

Sincere thanks to Sue and Paul Gebauer who ownWonga Wildlife Retreat in Coffs Harbour. Theyprovided us with a writer’s paradise. WithoutWonga the book would not be what it is today. Wealso extend our thanks to Chris and Rick Fryirs foruse of their Woodford house during the postreviewstage.

We extend our love to our families for their pa-tience and support over the many years it has takento write this book; Emmy, Zac, Whit, Chris, Rick,Steve, Sarah, Tim, Dee, Chris – thank you!

Self-evidently, many people have helped us alongthe way in a process that has provided many intel-lectual and personal challenges. Their insight andsupport have encouraged us to “maintain therage,” during countless phases when the projectdidn’t quite want to come to fruition. Indeed, wehope the book is far from an endpoint. As in anybook, ultimate responsibility in ideas presented liewith the authors. Our apologies, in advance, to any-one whose thoughts have been misrepresented.

1.1 Concern for river health

Rivers are a much-cherished feature of the naturalworld. They perform countless vital functions inboth societal and ecosystem terms, including per-sonal water consumption, health and sanitationneeds, agricultural, navigational, and industrialuses, and various aesthetic, cultural, spiritual, andrecreational associations. In many parts of theworld, human-induced degradation has profound-ly altered the natural functioning of river systems.Sustained abuse has resulted in significant alarmfor river health, defined as the ability of a river andits associated ecosystem to perform its naturalfunctions. In a sense, river health is a measure ofcatchment health, which in turn provides an indi-cation of environmental and societal health. It isincreasingly recognized that ecosystem health isintegral to human health and unless healthy riversare maintained through ecologically sustainablepractices, societal, cultural, and economic valuesare threatened and potentially compromised.Viewed in this way, our efforts to sustain healthy,living rivers provide a measure of societal healthand our governance of the planet on which we live.It is scarcely surprising that concerns for river con-dition have been at the forefront of conservationand environmental movements across much of theplanet.

In the past, the quest for security and stability to meet human needs largely overlooked the needsof aquatic ecosystems. In many instances, humanactivities brought about a suite of unintended and largely unconsidered impacts on river health,compromising the natural variability of rivers,their structural integrity and complexity, and the maintenance of functioning aquatic ecosys-

tems. Issues such as habitat loss, degradation, and fragmentation have resulted in significantconcerns for ecological integrity, sustainability,and ecosystem health. As awareness and under-standing of these issues has improved, society nolonger has an excuse not to address concernsbrought about by the impacts of human activitieson river systems. Shifts in environmental atti-tudes and practice have transformed outlooks and actions towards revival of aquatic ecosystems.Increasingly, management activities work in harmony with natural processes in an emerg-ing “age of repair,” in which contemporary management strategies aim to enhance fluvial environments either by returning rivers, to somedegree, to their former character, or by establishinga new, yet functional environment. Notable improvements to river health have been achievedacross much of the industrialized world in recent decades. However, significant communityand political concern remains over issues such as flow regulation, algal blooms, salinity, loss of habitat and species diversity, erosion and sedimentation problems, and water resource overallocation.

Rivers demonstrate a remarkable diversity oflandform patterns, as shown in Figure 1.1. Each ofthe rivers shown has a distinct set of landforms andits own behavioral regime. Some rivers have sig-nificant capacity to adjust their form (e.g., the me-andering, anastomosing, and braided river types),while others have a relatively simple geomorphicstructure and limited capacity to adjust (e.g., thechain-of-ponds and gorge river types). This vari-ability in geomorphic structure and capacity to ad-just, which reflects the array of landscape settingsin which these rivers are found, presents signifi-

CHAPTER 1

Introduction

Society’s ability to maintain and restore the integrity of aquatic ecosystems requires that conservation and management actions be firmly grounded in scientific understanding.

LeRoy Poff, et al., 1997, p. 769

2 Chapter 1

Figure 1.1 The diversity of river morphologyRivers are characterized by a continuum of morphological diversity, ranging from bedrock controlled variants such as(a) gorges (with imposed sets of landforms), to fully alluvial, self-adjusting rivers such as (c) braided and (d) meanderingvariants (with various midchannel, bank-attached and floodplain features). Other variants include multichanneledanastomosing rivers that form in wide, low relief plains (e), and rivers with discontinuous floodplain pockets in partly-confined valleys (b). In some settings, channels are discontinuous or absent, as exemplified by chain-of-ponds(f). Each river type has a different capacity to adjust its position on the valley floor. (a) Upper Shoalhaven catchment,New South Wales, Australia, (b) Clarence River, New South Wales, Australia, (c) Rakaia River, New Zealand, (d)British Columbia, Canada, (e) Cooper Creek, central Australia, and (f) Murrumbateman Creek, New South Wales,Australia.

Introduction 3

cant diversity in the physical template atop whichecological associations have evolved.

Developing a meaningful framework to recog-nize, understand, document, and maintain thisgeodiversity is a core theme of this book. Workingwithin a conservation ethos, emphasis is placed onthe need to maintain the inherent diversity ofriverscapes and their associated ecological values.Adhering to the precautionary principle, the high-est priority in management efforts is placed on

looking after good condition remnants of rivercourses, and seeking to sustain rare or uniquereaches of river regardless of their condition.

Just as there is remarkable diversity of riverforms and processes in the natural world, sohuman-induced disturbance to rivers is equallyvariable (see Figure 1.2). Many of these actionshave been intentional, such as dam construction,channelization, urbanization, and gravel or sandextraction. Far more pervasive, however, have

Figure 1.2 Human modifications to river coursesHuman modifications to rivers include (a) dams (Itaipu Dam, Brazil), (b) channelization (Ishikari River, Japan), (c)urban stream (Cessnock, New South Wales, Australia), (d) native and exotic vegetation removal (Busby’s Creek,Tasmania, Australia), (e) gravel and sand extraction (Nambucca River, New South Wales, Australia), and (f) mine effluent (King River, Tasmania, Australia).

4 Chapter 1

been inadvertent changes brought about throughadjustments to flow and sediment transfer regimesassociated with land-use changes, clearance of ri-parian vegetation, etc. Across much of the planet,remarkably few river systems even approximatetheir pristine condition. Most rivers now operateas part of highly modified landscapes in whichhuman activities are dominant.

The innate diversity of river courses is a sourceof inspiration, but it presents many perplexingchallenges in the design and implementation ofsustainable management practices. Unless man-agement programs respect the inherent diversityof the natural world, are based on an understandingof controls on the nature and rate of landscapechange, and consider how alterations to one part of an ecosystem affect other parts of that system,efforts to improve environmental condition arelikely to be compromised. River management pro-grams that work with natural processes will likelyyield the most effective outcomes, in environmen-tal, societal, and economic terms. Striving to meetthese challenges, truly multifunctional, holistic,catchment-scale river management programshave emerged in recent decades (e.g., Gardiner,1988; Newson, 1992a; Hillman and Brierley, inpress). Procedures outlined in this book can beused to determine realistic goals for river restora-tion and rehabilitation programs, recognizing theconstraints imposed by the nature and condition ofriver systems and the cultural, institutional, andlegal frameworks within which these practicesmust be applied.

1.2 Geomorphic perspectives on ecosystem

approaches to river management

Rivers are continuously changing ecosystems thatinteract with the surrounding atmosphere (climat-ic and hydrological factors), biosphere (biotic fac-tors), and earth (terrestrial or geological factors).Increasing recognition that ecosystems are open,nondeterministic, heterogeneous, and often innonequilibrium states, is prompting a shift inmanagement away from maintaining stable sys-tems for particular species to a whole-of-systemapproach which emphasizes diversity and fluxacross temporal and spatial scales (Rogers, 2002).Working within an ecosystem approach to natural

resources management, river rehabilitation pro-grams apply multidisciplinary thinking to addressconcerns for biodiversity and ecosystem integrity(Sparks, 1995). Inevitably, the ultimate goals ofthese applications are guided by attempts to bal-ance social, economic, and environmental needs,and they are constrained by the existing hydrologi-cal, water quality, and sediment transport regimesof any given system (Petts, 1996). Ultimately, how-ever, biophysical considerations constrain whatcan be achieved in river management. If riverstructure and function are undermined, such thatthe ecological integrity of a river is compromised,what is left? River rehabilitation programs framedin terms of ecological integrity must build on prin-ciples of landscape ecology. The landscape con-text, manifest through the geomorphic structureand function of river systems, provides a coherenttemplate upon which these aspirations must begrounded. The challenge presented to geomor-phologists is to construct a framework with whichto meaningfully describe, explain, and predict thecharacter and behavior of aquatic ecosystems.

Biological integrity refers to a system’s whole-ness, including presence of all appropriate bioticelements and occurrence of all processes and inter-actions at appropriate scales and rates (Angermeierand Karr, 1994). This records a system’s ability to generate and maintain adaptive biotic ele-ments through natural evolutionary processes.Ecosystem integrity requires the maintenance ofboth physico-chemical and biological integrity,maintaining an appropriate level of connectivitybetween hydrological, geomorphic, and bioticprocesses. While loss of biological diversity is tra-gic, loss of biological integrity includes loss of di-versity and breakdown in the processes necessaryto generate future diversity (Angermeier and Karr,1994). Endeavors to protect ecological integrity re-quire increased reliance on preventive rather thanreactive management, and a focus on landscapesrather than populations.

In riparian landscapes, aquatic, amphibious, andterrestrial species have adapted to a shifting mosa-ic of habitats, exploiting the heterogeneity that results from natural disturbance regimes (Junk et al., 1989; Petts and Amoros, 1996; Naiman andDecamps, 1997; Ward et al., 2002). This mosaic in-cludes surface waters, alluvial aquifers, riparianvegetation associations, and geomorphic features

Introduction 5

(Tockner et al., 2002). Because different organismshave different movement capacities and differenthabitat ranges, their responses to landscape het-erogeneity differ (Wiens, 2002). Fish diversity, forexample, may peak in highly connected habitats,whereas amphibian diversity tends to be highest inhabitats with low connectivity (Tockner et al.,1998). Other groups attain maximum species rich-ness between these two extremes. The resultingpattern is a series of overlapping species diversitypeaks along the connectivity gradient (Ward et al.,2002). Given the mutual interactions amongspecies at differing levels in the food chain, ecosys-tem functioning reflects the range of habitats inany one setting and their connectivity.

Landscape ecology examines the influence ofspatial pattern on ecological processes, consider-ing the ecological consequences of where thingsare located in space, where they are relative toother things, and how these relationships and theirconsequences are contingent on the characteris-tics of the surrounding landscape mosaic. The pat-tern of a landscape is derived from its composition(the kinds of elements it contains), its structure(how they are arranged in space), and its behavior(how it adjusts over time; Wiens, 2002). A land-scape approach to analysis of aquatic ecosystemsoffers an appropriate framework to elucidate thelinks between pattern and process across scales, to integrate spatial and temporal phenomena, toquantify fluxes of matter and energy across envi-ronmental gradients, to study complex phenome-na such as succession, connectivity, biodiversity,and disturbance, and to link research with man-agement (Townsend, 1996; Tockner et al., 2002;Ward et al., 2002; Wiens, 2002).

Principles from fluvial geomorphology provide aphysical template with which to ground landscapeperspectives that underpin the ecological integrityof river systems. Although landscape forms andprocesses, in themselves, cannot address all con-cerns for ecological sustainability and biodiversitymanagement, these concerns cannot be meaning-fully managed independent from geomorphologi-cal considerations. Working from the premise thatconcerns for ecological integrity are the corner-stone of river management practice, and that land-scape considerations underpin these endeavors,interpretation of the diversity, patterns, andchanging nature of river character and behavior

across a catchment is integral to proactive rivermanagement. This book outlines a generic set ofprocedures by which this understanding can beachieved.

Rehabilitation activities must be realisticallyachievable. Most riverscapes have deviated someway from their pristine, predisturbance condition.Hence, practical management must appraise whatis the best that can be achieved to improve thehealth of a system, given the prevailing boundaryconditions under which it operates. In instanceswhere human changes to river ecosystems are irre-versible or only partially reversible, a pragmaticdefinition of ecological integrity refers to themaintenance of a best achievable condition thatcontains the community structure and functionthat is characteristic of a particular locale, or a condition that is deemed satisfactory to society(Cairns, 1995). Specification of the goals of rivermanagement, in general, and river restoration, inparticular, has provoked considerable discussion,as highlighted in the following section.

1.3 What is river restoration?

The nature and extent of river responses to humandisturbance, and the future trajectory of change,constrain what can realistically be achieved inriver management (Figure 1.3; Boon, 1992). At oneextreme, conservation goals reflect the desire topreserve remnants of natural or near-intact sys-tems. Far more common, however, are endeavorsto rectify and repair some (or all) of the damage toriver ecosystems brought about by human activi-ties. Various terms used to describe these goals andactivities can be summarized using the umbrellaterm “restoration.”

Restoration means different things to differentpeople, the specific details of which may promoteconsiderable debate and frustration (Hobbs andNorton, 1996). Although the term has been appliedto a wide range of management processes/activi-ties, its precise meaning entails the uptake ofmeasures to return the structure and function of asystem to a previous state (an unimpaired, pris-tine, or healthy condition), such that previous attributes and/or values are regained (Bradshaw,1996; Higgs, 2003). In general, reference is made topredisturbance functions and related physical,

6 Chapter 1

chemical, and biological characteristics (e.g.,Cairns, 1991; Jackson et al., 1995; Middleton,1999).

The few studies that have documented geomor-phic attributes of relatively intact or notionallypristine rivers (e.g., Collins and Montgomery,2001; Brooks and Brierley, 2002), and countlessstudies that have provided detailed reconstruc-tions of river evolution over timescales of decades,centuries, or longer, indicate just how profoundhuman-induced changes to river forms andprocesses have been across most of the planet. It isimportant to remember the nonrepresentative na-ture of the quirks of history that have avoided theprofound imprint of human disturbance. Intactreaches typically lie in relatively inaccessibleareas. They are seldom representative of the areasin which management efforts aim to improve riverhealth. However, it is in these reaches, and adjacent good condition reaches, that efforts atrestoration can meaningfully endeavor to attainsomething akin to the pure definition of the word.

Viewed in a more general sense, restorationrefers to a management process that provides ameans to communicate notions of ecosystem re-covery (Higgs, 2003). For example, the Society forEcological Restoration (SERI, 2002) state that

restoration refers to the process of assisting the re-covery of an ecosystem that has been degraded,damaged, or destroyed. The notion of recovery de-scribes the process of bringing something back.

Endeavors that assist a system to adjust towardsa less stressed state, such that there is an improve-ment in condition, are more accurately referred toas river rehabilitation. Rehabilitation can meanthe process of returning to a previous condition orstatus along a restoration pathway, or creation of anew ecosystem that previously did not exist (Fryirsand Brierley, 2000; Figure 1.3). In landscapes sub-jected to profound human disturbance, such asurban, industrial, or intensively irrigated areas,management activities inevitably work towardscreation goals. Both restoration and creation goalsrequire rehabilitation strategies that strive to im-prove river condition, applying recovery notions towork towards the best attainable ecosystem valuesgiven the prevailing boundary conditions. The es-sential difference between restoration and cre-ation goals lies in the perspective of regeneratingthe “old” or creating a “new” system (Higgs, 2003).

Various other terms have been used to character-ize practices where the goals are not necessarilyframed in ecosystem terms. For example, reclama-tion refers to returning a river to a useful or proper

Figure 1.3 Framing realistic management options – what can be realistically achieved?Determination of river rehabilitation goals isconstrained primarily by what it is realisticallypossible to achieve. This reflects systemresponses to human disturbance, the prevailingset of boundary conditions, and the likely futuretrajectory of change (as determined by limitingfactors and pressures operating within thecatchment and societal goals). Maintenance ofan intact condition is a conservation goal. If areturn to a predisturbance state is possible anddesirable, rehabilitation activities can applyrecovery principles to work towards arestoration goal. In many instances, adoption ofa creation goal, which refers to a new conditionthat previously did not exist at the site, is theonly realistic option.

Introduction 7

state, such that it is rescued from an undesirablecondition (Higgs, 2003). In its original sense, recla-mation referred to making land fit for cultivation,turning marginal land into productive acreage.Alternatively, remediation refers to the process ofrepairing ecological damage in a manner that doesnot focus on ecological integrity and is typicallyapplied without reference to historical conditions(Higgs, 2003). Reclamation and remediation arequick-fix solutions to environmental problemsthat address concerns for human values, viewedseparately from their ecosystem context.

The purpose and motivation behind any rehabil-itation activity are integral to the goal sought.Specification of conservation, restoration, or cre-ation goals provides an indication of the level andtype of intervention that is required to improveriverine environments.

1.4 Determination of realistic goals in river

rehabilitation practice

The process of river rehabilitation begins with ajudgment that an ecosystem damaged by humanactivities will not regain its former characteristicproperties in the near term, and that continueddegradation may occur (Jackson et al., 1995).Approaches to repair river systems may focus onrehabilitating “products” (species or ecosystems)directly, or on “processes” which generate the de-sired products (Neimi et al., 1990; Richards et al.,2002). However, unless activities emphasize concerns for the rehabilitation of fundamentalprocesses by which ecosystems work, notions ofecosystem integrity and related measures of biodi-versity may be compromised (Cairns, 1988).

The goal of increasing heterogeneity across thespectrum of river diversity represents a flawed per-ception of ecological diversity and integrity. Insome cases, the “natural” range of habitat struc-ture may be very simple. Hence, heterogeneity orgeomorphic complexity does not provide an appro-priate measure of river health (see Fairweather,1999). Simplistic goals framed in expressions suchas “more is better” should be avoided (Richards etal., 2002). Use of integrity as a primary manage-ment goal avoids the pitfalls associated with assumptions that greater diversity or productiv-ity is preferred.

Unlike many biotic characteristics, physicalhabitat is directly amenable to managementthrough implementation of rehabilitation pro-grams (Jacobson et al., 2001). Hence, many man-agement initiatives focus on physical habitatcreation and maintenance, recognizing that geomorphic river structure and function and vegetation associations must be appropriately reconstructed before sympathetic rehabilitationof riverine ecology will occur (Newbury andGaboury, 1993; Barinaga, 1996). Getting the geo-morphological structure of rivers right maximizesthe ecological potential of a reach, in the hope thatimprovements in biological integrity will follow(i.e., the “field of dreams” hypothesis; Palmer etal., 1997). The simplest procedure with which todetermine a suitable geomorphic structure andfunction is to replicate the natural character of“healthy” rivers of the same “type,” analyzed inequivalent landscape settings.

In any management endeavor, it is imperative toidentify, justify, and communicate underlyinggoals, ensuring that the tasks and plan of action arevisionary yet attainable. Although setting goals forrehabilitation is one of the most important steps indesigning and implementing a project, it is ofteneither overlooked entirely or not done very well(Hobbs, 2003). Success can only be measured if adefinitive sense is provided of what it will looklike. Unfortunately, however, there is a tendencyto jump straight to the “doing” part of a projectwithout clearly articulating the reasons whythings are being done and what the outcomeshould be (Hobbs, 1994, 2003).

While sophisticated methodologies and tech-niques have arisen in the rapidly growing field ofrehabilitation management, the conceptual foun-dations of much of this work remain vague(Ebersole et al., 1997). The pressure of timeframes,tangible results, and political objectives has lead to a preponderance of short-term, transitory re-habilitation projects that ignore the underlying capacities and developmental histories of the systems under consideration, and seldom place the study/treatment reach in its catchment con-text (Ebersole et al., 1997; Lake, 2001a, b).Unfortunately, many of these small-scale aquatichabitat enhancement projects have failed, or haveproven to be ineffective (e.g., Frissell and Nawa,1992).

8 Chapter 1

Ensuring that goals are both explicit enough tobe meaningful and realistic enough to be achiev-able is a key to the development of successful pro-jects. Ideally, goals are decided inclusively, so thateveryone with an interest in the outcomes of theproject agrees with them (Hobbs, 2003). Scopingthe future and generating a realistic vision of thedesired river system are critical components of theplanning process. The vision should be set over a50 year timeframe (i.e., 1–2 generations; Jackson etal., 1995), such that ownership of outcomes can beachieved. A vision must be based on the best avail-able information on the character, behavior, andevolution of the system, providing a basis to inter-pret the condition and trajectory of change fromwhich desired future conditions can be established(Brierley and Fryirs, 2001). These concepts must betied to analysis of biophysical linkages across arange of scales, enabling off-site impacts andlagged responses to disturbance events and/or re-habilitation treatments to be appraised (Boon,1998).

To maximize effectiveness, rehabilitation ef-forts should incorporate spatiotemporal scalesthat are large enough to maintain the full range of habitats and biophysical linkages necessary forthe biota to persist under the expected distur-bance regime or prevailing boundary conditions.Although emphasis may be placed on a particularcomponent or attribute, ultimate aims of long-term projects should focus on the whole system atthe catchment scale (Bradshaw, 1996). Desiredconditions for each reach should be specified asconservation, restoration, or creation goals, indi-cating how they fit within the overall catchmentvision. Appropriate reference conditions should bespecified for each reach.

Defining what is “natural” for a given type ofriver that operates under a certain set of prevailingboundary conditions provides an important step inidentification of appropriate reference conditionsagainst which to measure the geoecological in-tegrity of a system and to identify target conditionsfor river rehabilitation. A “natural” river is definedhere as “a dynamically adjusting system that be-haves within a given range of variability that is appropriate for the river type and the boundaryconditions under which it operates.” Within thisdefinition, two points of clarification are worthnoting. First, a “natural” condition displays the

full range of expected or appropriate structures andprocesses for that type of river under prevailingcatchment boundary conditions. This does notnecessarily equate to a predisturbance state, ashuman impacts may have altered the nature, rate,and extent of river adjustments (Cairns, 1989).Second, a dynamically adjusted reach does not nec-essarily equate to an equilibrium state. Rather, theriver adjusts to disturbance via flow, sediment, andvegetation interactions that fall within the naturalrange of variability that is deemed appropriate forthe type of river under investigation.

Determination of appropriate reference condi-tions, whether a fixed historical point in time or a suite of geoecological conditions, represents acritical challenge in rehabilitation practice (Higgs,2003). Systems in pristine condition serve as apoint of reference rather than a prospective goal forriver rehabilitation projects, although attributes ofthis ideal condition may be helpful in rehabilita-tion design. Identification of reference conditionsaids interpretation of the rehabilitation potentialof sites, thereby providing a basis to measure thesuccess of rehabilitation activities.

Reference conditions can be determined on thebasis of historical data (paleo-references), data de-rived from actual situations elsewhere, knowledgeabout system structure and functioning in general(theoretical insights), or a combination of thesesources (Petts and Amoros, 1996; Jungwirth et al.,2002; Leuven and Poudevigne, 2002). The morpho-logical configuration and functional attributes of areference reach must be compatible with prevail-ing biophysical fluxes, such that they closelyequate to a “natural” condition for the river type.Ideally, reference reaches are located in a similarposition in the catchment and have near equiva-lent channel gradient, hydraulic, and hydrologicconditions (Kondolf and Downs, 1996).Unfortunately, it is often difficult to find appropri-ate reference conditions for many types of river, as “natural” or minimally impacted reaches nolonger exist (Henry and Amoros, 1995; Ward et al.,2001). In the absence of good condition remnants,reference conditions can be constructed from his-torical inferences drawn from evolutionary se-quences that indicate how a river has adjusted overan interval of time during which boundary condi-tions have remained relatively uniform. Selectionof the most appropriate reference condition is situ-

Introduction 9

ated within this sequence. Alternatively, a suite ofdesirability criteria derived for each type of rivercan be used to define a natural reference conditionagainst which to compare other reaches (Fryirs,2003). These criteria must encapsulate the formsand processes that are “expected” or “appropriate”for the river type. They draw on system-specificand process-based knowledge, along with findingsfrom analysis of river history and assessment ofavailable analogs. This approach provides a guid-ing image, or Leitbild, of the channel form thatwould naturally occur at the site, adjusted to ac-count for irreversible changes to controlling fac-tors (such as runoff regime) and for considerationsbased on cultural ecology (such as preservation ofexisting land uses or creation of habitat for endan-gered species; Kern, 1992; Jungwirth et al., 2002;Kondolf et al., 2003). Leitbilds can be used to pro-vide a reference network of sites of high ecologicalstatus for each river type, as required by theEuropean Union Water Framework Directive.

1.5 Managing river recovery processes in river

rehabilitation practice

Exactly what is required in any rehabilitation ini-tiative will depend on what is wrong. Options mayrange from limited intervention and a leave-alonepolicy, to mitigation or significant intervention,depending on how far desired outcomes are fromthe present condition. In some instances, sensi-tive, critical, or refuge habitats, and the stressors or constraints that limit desirable habitat, must be identified, and efforts made to relieve thesestressors or constraints (Ebersole et al., 1997).Controlling factors that will not ameliorate natu-rally must be identified, and addressed first.Elsewhere, rehabilitation may involve the reduc-tion, if not elimination, of biota such as successfulinvaders, in the hope of favoring native biota(Bradshaw, 1996). For a multitude of reasons, rang-ing from notions of naturalness that strive to pre-serve “wilderness,” to abject frustration at theinordinate cost and limited likelihood of successin adopted measures (sometimes referred to as bas-ket cases, or “raising the Titanic”; Rutherfurd et al., 1999), it is sometimes advisable to pursue apassive approach to rehabilitation. This strategy,often referred to as the “do nothing option,” allows

the river to self-adjust (cf., Hooke, 1999; Fryirs andBrierley, 2000; Parsons and Gilvear, 2002; Simonand Darby, 2002). Although these measures entailminimal intervention and cost, managers havenegligible control over the characteristics andfunctioning of habitats (Jacobson et al., 2001).

In general terms, however, most contemporaryapproaches to river rehabilitation endeavor to“heal” river systems by enhancing natural recov-ery processes (Gore, 1985). Assessment of geomor-phic river recovery is a predictive process that isbased on the trajectory of change of a system in re-sponse to disturbance events. Recovery enhance-ment involves directing reach development alonga desired trajectory to improve its geomorphic con-dition over a 50–100 year timeframe (Hobbs andNorton, 1996; Fryirs and Brierley 2000; Brierley et al., 2002). To achieve this goal, river rehabilita-tion activities must build on an understanding ofthe stage and direction of river degradation and/orrecovery, determining whether the geomorphiccondition of the river is improving, or continuingto deteriorate.

Assessment of geomorphic river conditionmeasures whether the processes that shape rivermorphology are appropriate for the given setting,such that deviations from an expected set of attrib-utes can be appraised (Figure 1.4; Kondolf andLarson, 1995; Maddock, 1999). Key considerationmust be given to whether changes to the boundaryconditions under which the river operates havebrought about irreversible changes to river struc-ture and function (Fryirs, 2003). Identification of good condition reaches provides a basis for their conservation. Elsewhere, critical forms andprocesses may be missing, accelerated, or anom-alous, impacting on measures of geoecologicalfunctioning.

Understanding of geomorphic processes andtheir direction of change underpins rehabilitationstrategies that embrace a philosophy of recoveryenhancement (Gore, 1985; Heede and Rinne, 1990;Milner, 1994). Helping a river to help itself pres-ents an appealing strategy for river rehabilitationactivities because they cost nothing in themselves(although they may cost something to initiate),they are likely to be self-sustaining because theyoriginate from within nature (although they mayneed nurturing in some situations), and they canbe applied on a large scale (Bradshaw, 1996). Design

10 Chapter 1

and implementation of appropriate monitoringprocedures are integral in gauging the success ofthese strategies.

The process of river rehabilitation is a learningexperience that requires ongoing and effectivemonitoring in order to evaluate and respond tofindings. Measuring success must include the pos-sibility of measuring failure, enabling midcoursecorrections, or even complete changes in direction(Hobbs, 2003). If effectively documented, eachproject can be considered as an experiment, so thatfailure can be just as valuable to science as success,provided lessons are learnt. Goals or performancetargets must be related to ecological outcomes andbe measurable in terms such as increases in healthindicators (e.g., increasing similarity of species or

structure with the reference community), or de-creases in indicators of degradation (e.g., activeerosion, salinity extent or impact, nonnative plantcover). The choice of parameters to be monitoredmust go hand in hand with the setting of goals, en-suring that they are relevant to the type of riverunder consideration, so that changes in conditioncan be meaningfully captured. Baseline data are re-quired to evaluate changes induced by the project,including a detailed historical study (Downs andKondolf, 2002). Monitoring should be applied overan extensive period, at least a decade, with surveysconducted after each flood above a predeterminedthreshold (Kondolf and Micheli, 1995). These vari-ous components are integral parts of effective riverrehabilitation practice.

Figure 1.4 Habitat diversity for good, moderate, and poor condition variants of the same river typeNatural or expected character and behavior varies for differing types of river. Some may be relatively complex, othersare relatively simple. Natural species adaptations have adapted to these conditions. Assessments of geomorphic rivercondition must take this into account, determining whether rehabilitation activities should increase (a) or decrease (b)the geomorphic heterogeneity of the type of river under investigation. Increasing geomorphic heterogeneity is not anappropriate goal for all types of river, and may have undesirable ecological outcomes. More appropriate strategies workwith natural diversity and river change.

Introduction 11

1.6 Overview of the River Styles framework

Best practice in natural resources management re-quires appropriate understanding of the resourcethat is being managed, and effective use of the best available information. In river managementterms, catchment-scale information on the char-acter, behavior, distribution, and condition of different river types is required if managementstrategies are to “work with nature.” Given thatrivers demonstrate remarkably different charac-ter, behavior, and evolutionary traits, both between- and within-catchments, individualcatchments need to be managed in a flexible man-ner, recognizing what forms and processes occurwhere, why, how often, and how these processeshave changed over time. The key challenge is tounderstand why rivers are the way they are, howthey have changed, and how they are likely to lookand behave in the future. Such insights are funda-mental to our efforts at rehabilitation, guidingwhat can be achieved and the best way to get there.

This book presents a coherent set of proceduralguidelines, termed the River Styles framework,with which to document the geomorphic struc-ture and function of rivers, and appraise patterns ofriver types and their biophysical linkages in acatchment context. Meaningful and effective de-scription of river character and behavior are tied toexplanation of controls on why rivers are the waythey are, how they have evolved, and the causes ofchange. These insights are used to predict likelyriver futures, framed in terms of the contemporarycondition, evolution, and recovery potential of anygiven reach, and understanding of its trajectory ofchange (Figure 1.5).

The River Styles framework is a rigorous yetflexible scheme with which to structure observa-tions and interpretations of geomorphic forms andprocesses. A structured basis of enquiry is appliedto develop a catchment-wide package of physicalinformation with which to frame management ac-tivities (Figure 1.6). This package guides insightsinto the type of river character and behavior that isexpected for any given field setting and the type ofadjustments that may be experienced by that typeof river. A catchment-framed nested hierarchicalarrangement is used to analyze landscapes interms of their constituent parts. Reach-scale formsand processes are viewed in context of catchment-

scale patterns and rates of biophysical fluxes.Separate layers of information are derived to ap-praise river character and behavior, geomorphiccondition, and recovery. Definition of ongoing ad-justments around a characteristic state(s) enablesdifferentiation of the behavioral regime of a givenriver type from river change. Analysis of systemevolution is undertaken to appraise geomorphicriver condition in context of “expected attributes”of river character and behavior given the reach set-ting. Interpretation of catchment-specific linkagesof biophysical processes provides a basis withwhich to assess likely future patterns of adjust-ment and the geomorphic recovery potential ofeach reach. The capacity, type, and rate of recoveryresponse of any given type of river are dependenton the nature and extent of disturbance, the inher-ent sensitivity of the river type, and the operationof biophysical fluxes (both now and into the future)at any given point in the landscape. When these no-tions are combined with interpretations of limit-ing factors to recovery and appraisal of ongoing andlikely future pressures that will shape river formsand processes, a basis is provided to assess likelyfuture river condition, identify sensitive reachesand associated off-site impacts, and determine thedegree/rate of propagating impacts throughout acatchment.

The strategy outlined in this book emphasizesthe need to understand individual systems, theiridiosyncrasies of forms and processes, and evolu-tionary traits and biophysical linkages, as a basis to

Figure 1.5 Routes to description, explanation, and prediction

12 Chapter 1

fl

fl

fl

Figure 1.6 Stages of the River Stylesframework

determine options for management – in planning,policy, and design terms. System configurationand history ensure that each catchment is unique.In making inferences from system-specific infor-mation, cross-reference is made to theoretical andempirical relationships to explain system behav-ior and predict likely future conditions. Principlesoutlined in this book provide a conceptual toolwith which to read and interpret landscapes, ratherthan a quantitative approach to analysis of riverforms and processes. Application of these proce-dures provides the groundwork for more detailedsite- or reach-specific investigations.

However, application of geomorphic principlesin the determination of sustainable river manage-ment practices is far from a simple task. The needfor system-specific knowledge and appropriateskills with which to interpret river evolution andthe changing nature of biophysical linkages (andtheir consequences) ensure that such exercisescannot be meaningfully undertaken using a pre-scriptive cook-book approach. The cautious, dataintensive measures applied in this book are con-sidered to present a far better perspective thanmanaging rivers to some norm! Hopefully, lessonshave been learnt from the homogenization of rivercourses under former management regimes.

Management applications of the River Stylesframework focus on the derivation of a catchment-scale vision for conservation and rehabilitation,identification of reach-specific target conditionsthat fit into the bigger-picture vision, and applica-tion of a geomorphologically based prioritizationprocedure which outlines the sequencing of ac-tions that best underpins the likelihood of man-agement success. The framework does not providedirect guidance into river rehabilitation design and

selection of the most appropriate technique.Rather, emphasis is placed on the need to appraiseeach field situation separately, viewed within itscatchment context and evolutionary history. Theunderlying catchcry in applications of the RiverStyles framework is “KNOW YOUR CATCH-MENT.”

1.7 Layout and structure of the book

This book comprises four parts (Figure 1.7). Part Aoutlines the geoecological basis for river manage-ment. Chapter 2 documents the use of geomor-phology as a physical template for integratingbiophysical processes, working with linkages ofbiophysical processes within a catchment frame-work, and the need to respect diversity (work withnature). Chapter 3 outlines how geomorphic prin-ciples provide a basis for river management pro-grams to work with change through understandingof controls on river character and behavior and pre-diction of likely future adjustments.

Geomorphic principles that underpin applica-tions of the River Styles framework are document-ed in Part B. Pertinent literature is reviewed toassess river character (Chapter 4), interpret riverbehavior (Chapter 5), analyze river evolution andchange (Chapter 6), and appraise river responses tohuman disturbance (Chapter 7).

The River Styles framework is presented in PartC. An overview of the framework in Chapter 8 isfollowed by a brief summary of practical and logis-tical issues that should be resolved prior to its application. Chapter 9 presents the step-by-stepprocedure used to classify and interpret river char-acter and behavior in Stage One of the framework.

Introduction 13

Figure 1.7 Structure of the book

14 Chapter 1

Procedures used to assess geomorphic condition ofrivers in Stage Two of the framework are presentedin Chapter 10. Evolutionary insights are used to in-terpret the future trajectory and recovery potentialof rivers in Stage Three of the framework (Chapter11). Finally, Chapter 12 outlines Stage Four of theRiver Styles framework, which can be used to de-velop catchment-framed visions for management,

identify target conditions for river rehabilitation,and prioritize where conservation and rehabilita-tion should take place.

The concluding chapter, in Part D, outlines anoptimistic (aspirational) perspective on futureriver management practices and outcomes(Chapter 13).

Overview of Part A

This part demonstrates how principles from fluvial geomorphology can be used to develop anecosystem approach to river analysis and manage-ment. In Chapter 2, spatial considerations in geo-morphology and management practice are framedin terms of a nested hierarchical approach to catch-ment characterization. Principles from fluvial geo-morphology are shown to provide an integrativephysical template with which to assess habitat as-sociations and linkages of biophysical processes inlandscapes. Finally, the concept of respecting di-versity is introduced, indicating why management

strategies should strive to maintain unique or dis-tinctive attributes of river courses.

Chapter 3 outlines how theoretical and field-based insights must be combined to meaningfullydescribe and explain river systems. These insightsprovide a critical platform for our efforts at predic-tion. Themes discussed in this chapter include the need for management programs to work withchange, moving beyond notions of equilibriumand stability used in engineering applications.Timeframes of river adjustment, assessment ofcontrols on river character and behavior, and ap-proaches to prediction are also outlined.

PART A

The geoecological basis of

river management

(A)n understanding of the nature of the building blocks that compose a particular landscape isfundamental to understanding how geomorphological processes function as ecological disturbance processes at the watershed or landscape scale.

Dave Montgomery, 2001, p. 249